A theft preventive device comprising such a detector for theft prevention is used in contact with an object of theft prevention such as a commodity displayed in a shop, for example; The detector for theft prevention detects whether the theft preventive device has been detached from the object of theft prevention, and sounds an alarm.
As shown in FIG. 25, for example, a theft preventive device 100 is mounted in a case 101 to protect, from shoplifting, an object of theft prevention E such as a compact disk. The object of theft prevention E is inserted into the case 101 to contact the theft preventive device 100 (see, for example, Utility Model Application No. 3-11054 filed by Applicant).
A switch is provided for the theft preventive device as a detector for theft prevention to detect whether the theft preventive device has been detached from the object of theft prevention then. The switch has a pivotable operated portion biased to return to a position projected from a contact surface of the object of theft prevention. However, as shown in FIG. 26, the conventional operated portion can pivot only to one side from the projected position.
In the figure, 3' denotes a conventional switch having an operated portion 3a', and 102 denotes an alarm generator.
Since the conventional operated portion is pivotable only to one side from the projected position, the object of theft prevention cannot be moved in a direction that pivots the operated portion in a direction other than that direction.
Thus, when inserting the object of theft prevention E into the case 101, the object of theft prevention E is moved in a direction f1 as shown in FIG. 26. When removing the object of theft prevention from the case 101, the object of theft prevention E is moved in a direction f2. If the object of theft prevention E has an uneven contact surface (lower surface), the operated portion 3a' is caught on the unevenness when the object of theft prevention E is moved out of the case 101. Thus, the object of theft prevention E cannot be taken out. When an attempt is made to take out the object of theft prevention E forcibly, the operated portion 3a' could be damaged inadvertently.
An object of the present invention is to provide a detector for theft prevention that eliminates the drawbacks of the prior art noted above.
More particularly, the invention intends to provide a detector for theft prevention operable properly with regard to various directions of movement of an object of theft prevention, for example.
Furthermore, the invention intends to provide a detector for theft prevention having little chance of malfunction, capable of reliably detecting whether a theft preventive device has been detached or not, and having a high yield of manufacture.